When it comes to boats no issue like hull shape and displacement can get disagreements between people.(and just about anything else when it comes to boats)Then ask about bluewater?It is like choosing ones religion,answers come from within.Like Jack said read all you can and find which works for you.Definitions for the most part become interpretations.

Jack, this is a very poor way to exchange views. You missed completely my point and probably that was my fault. Let me try again.

I don’t think the RCD was implemented as a Trade Barrier (there was almost no US sail boats in the EU market, and the situation didn’t change with the RCD). I think that has to do with a global policy (sometimes a true obsession) in ruling everything and giving information to the consumer about everything. This legislative “obsession” has to do mainly with safety and ecology and normally it is a pain in the ass, resulting mainly in a lot of paper work.

Regarding RCD it is the same thing, as you say, manufacturers had certainly influenced the draft in the definition of the categories (and I have said in a previous post that I consider the standards for A class/unlimited inadequately low) and on site compliance visits are mainly a paper work affair.

What is very interesting in the RCD is a small but very important part that escaped to the burocrats and that is Stability. I am not talking about the standards of stability for each class, but in the way it is measured in each boat. This part of the problem was “given” to the British technicians that had a lot of experience in the matter (RYA and RORC) and they have made an outstanding job.

What you have now, is reliable stability information on each model of boat, because they need to have all the data to be classified. I am not talking about classes, I am talking about true and raw information about every aspect of the boat stability (initial, reserve, AVS, GZ, RM curve) that is public and available to you. With this information you can
make your standard and look at the type of boat that suits you.

They have even devised, for the consumers that don’t know what to do with all that data, a smart and relatively accurate way to estimate the global “value” of the boat stability (STIX).

To understand why I say that the stability data is relatively sound you have to consider this:

The process of measuring all the data that permits the evaluation of a boat is not made occasionally in the factory, nor is it made by burocrats. It is a technical work made only one time for each model and part of the measures are taken in the water with inclination tests. Later in the factory, one or two times a year they check the conformity of the production with the test prototype.

Those measurements are not made by the builder but by independent, technical and very specialized private agencies holding a permit given by the EU that attests their independence and competence to do the job. The measures are made according to a very precise set of rules defined by ISO 12217.

I don’t know how things are made there, but it is not believable that one of those agencies would “fake” measures. It would lose its license and be prosecuted. Any obvious fake would be very noticeable to competing brands with similar models.

You seem to think that the builders have a commercial interest in publicizing stability data.

They don’t.

I only know two builders that publicized these data, both uppermarket really ocean going boats with very good stability. Boats with very good stability are very expensive, because mass is part of the equation and it doesn’t make sense to make a very stable boat without making also a very solid one.

Big builders, like Beneteau, Jeaneau, Bavaria never publicize the stability of their boats and you only get stability data if the seller realizes that he will lose a potential client if he doesn’t provide that information.

The RYA has been complaining (without success) for a long time, saying that those figures should be mandatory in the publicity of the boats, as it is in cars for consumption and emissions.

Finally things begin to change because British Sailing Magazines started a policy of only testing a new boat if they have access and can publish the Stix and GZ curve. German magazines seem to go the same way.

Sorry for the long post, but I believe that these data, if accurate, will give everybody a better understanding of the different boats and will help everyone to chose the right boat .

About the value of STIX as a useful tool to assess a boat stability I have found of interest the opinion that Bob Johnson (president of Island Packet Yacht) wrote in a letter published in the last special issue of Sail Magazine:

...."As the U.S. participant on the international work group of designers and naval architects responsible for developing this particular ISO standard, I''d like to provide some background on its development and shed some light on why I believe it will grow to have considerable value to both the design community and the boat owner."

" As Dave''s article illustrates, the accurate stability assessment of any sailboat is a complex process. Numerous design characteristics influence the ability of any boat to safely resist or recover from capsize, ranging from downflooding openings to the shape of its righting-moment curve. In all, the ISO work group found that seven different calculated factors encompassed all significant stability concerns and, taken together, could establish a single stability index value (STIX) that allows meaningful stability comparisons between various designs."

"The minimum STIX value for each category was created and validated from a study of a large number of existing sailboats, ranging in size and type, that had experienced capsize events, with and without successful recovery. Good correlation was eventually obtained between theory and practice, and the final STIX standard, I think, encompasses all critical stability factors in an analytical method that is based on established principles of naval architecture, sound methodology, and correlates well with real-world experience for real boats. No other single stability-assessment method, to my knowledge, is as comprehensive as STIX. "

...."Lastly, I’d like to comment on the Capsize Screen method mentioned in another sidebar. This was proposed in the 1985 USYRU and SNAME Joint Committee Report on Safety from Capsizing (prompted by the 1979 Fastnet disaster). As Dave correctly states, and I heartily reinforce, by itself the capsize screen evaluation method has virtually no value in the assessment of a yacht''s stability. It''s really addressing a concern that lightweight designs with a wide beam are suspect regarding their susceptibility to capsize, justifying further stability evaluation. One of the seven STIX factors addresses this very issue.

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Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

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I'm just getting my thoughts together in the sail mode after several years in the powerboat "thing"... certainly there must be somebody that agrees on something....while I'm getting a late start...I'd like to find a nice boat that can be sailed with two or single handed...in the Gulf...and Carib...I'm 65....with all of the STIX, AVS and RCD's....whew...can get confusing....displacement, length....

From there (Some small parts of text have been changed, not to repeat everything posted there):

Well, thinking CE marking is not conceived for racing boats, but for the recreational market, where most of cruising boats are short handed and boats should look after their crews, in my humble opinion, I think it's worrying that some boats can be labelled as Category A, taking into consideration they have what has been commonly understood for many years, among designers, NA’s and boat owners, as 'cruel' and even dangerous ratios and parameters. Those boats are too stiff by all means, with a low motion comfort ratio, too high accelerations (And so quite punishing for a short handed crew) and with Capsize Safety Factor well above 2, widespread considered a safe limit.

In my opinion STIX provides not enough information about the seaworthiness of a boat (It was never intended to be a clue to this, but this idea is spreading around quickly) and may even be a tricky and dangerous number. Seaworthiness is a complex matter, involving stability, all around scantlings, quality of movements, and a long etc.

I think manufacturers/designers should at least be obliged to publicize the STIX Factors and not only the number itself (Which is not even mandatory!). And even better, publish also the 'old' ratios and parameters, for the people to have a more complete view and understanding of the boat.

Rolf Eliasson (One of the fathers of the STIX number) himself expressed some serious concerns about the STIX number and how it finally 'came to life', in the aforementioned article. He even suggested minimum STIX for Categories A and B should be 40 and 28, instead of 32 and 23 as it is now. But even rising the level provides not enough guarantee as to define a boat as seaworthy, as we could see per numbers above.

Again in my opinion, most probably a great pressure from modern mass (and light) boats producers (and their designers) was put into the process. Those manufacturers produce very nice boats for Club racing and coastal cruising in fair weather (what most of users do) and fun to sail, but of course they want not many of their models to be obliged to be labelled as Category C, what they should be in most cases.

Long range racing is quite a different thing (with full trained crews aboard), than family oceans crossings so, in my opinion, CE Category's assigning criteria should be revised and adequate to the RCD’s own reason of existing. If racing is intended, a new special Category or Note should apply in addition to the ‘familiy’ Category.

“I doubt anyone has the STIX ratings published, as much will depend on how you have the boat loaded and rigged, and where you have supplies and equipment stowed”.

Hellosailor:

"Can anyone point me to a URL listing various boats and their STIX ratings, so I can get an idea of which rates for what?"

PCP:

Sorry for taking so long in repling, but I don’t have been around this Forum.

The stix doesn’t change that much with the boat loaded, unless you load it over the Maximum load capacity. Anyway now they have to show the calculations for two STIXs, One in the minimum loading displacement and the other in the Max loading displacement. Normally the difference is not bigger than 1 point.

I will post my opinion about the STIX, as posted in another boatforum and some others more relevant as well as a short list with sailboat’s STIXs.

STIX:

STIX it is an evaluation for an existing Yacht about its stability and seaworthiness. It is intended not for professional, but for the common user, just to give him a correct idea of the seaworthiness of a given boat.

It is in that sense that RYA says that: “just the same way it is mandatory for the fuel consumption of all new cars to be published…that stability information should also be available to a buyer of a boat”.

STIX is only an easily understandable index (but found through a complicated calculation that takes into account a lot of different stability factors) that is in my opinion, the most sophisticated stability screening tool available.

Certainly very superior to the old Stability Indexes, that in many cases were very misleading and were not unified. I mean, you needed to take a look at several to have an idea of the boat, and many times a wrong idea, mainly with modern deep drafted bulbed yachts.

Don’t get me wrong, it is not a perfect tool, (only the best until now).

Personally I take a look at the STIX for having a general idea, but my evaluation is done independently by the analysis of the RM curve and done by a close examination of the boat (and I mean not a virtual one), with answers about the way it is built and the kind of materials that are used. Special incidence in the way the keel is fixed to the boat, about the rudder and about the hatches and all the “glass” surfaces and the way they are secured to the boat. Not that these are the only important points, but if special care is taken with these ones, there is a good possibility that all the others are well taken care of.

But for understanding a RM curve correctly you have to know a lot more.

STIX is just a number and its interpretation could not be simpler: The bigger, the better.

The RYA view about STIX:

“STIX is arguably the most sophisticated stability screening tool yet available. ….
Since June 1998 all new recreational boats sold in the EU have been required by law (the RCD*) to have undergone a stability assessment with the preferred method being the application of ISO 12217. “

The Paul Miller view (D. Engr., from the Dept. of Naval Architecture of the United States Naval Academy:

“The Best we have…”

Bob Johnson view: (Naval architect, the Island Packets designer and the U.S. participant on the international work group of designers and naval architects responsible for developing STIX):

… STIX standard, I think, encompasses all critical stability factors in an analytical method that is based on established principles of naval architecture, sound methodology, and correlates well with real-world experience for real boats. No other single stability-assessment method, to my knowledge, is as comprehensive as STIX.

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